Because of its excellent material properties polysilicon is the chief material used in the formation of integrated circuits.
In order to take advantage of the emerging technology of faster and smaller integrated circuit devices, it is necessary to develop new materials which can be used as interconnection and gate materials instead of, or in conjunction with, polysilicon. These materials must have lower resistivity than polysilicon and should be compatible with current integrated circuit processes. Silicides of refractory metals (Mo, W, Ti and Ta) with their metallic conductivity and high temperature stability, meet these requirements.
Refractory metal silicides are most commonly prepared by some form of Physical Vapor Deposition (PVD) process, such as, sputtering or co-evaporation. However, Chemical Vapor Deposition (CVD) with its advantages of good conformal coverage, high throughput and purity promises to be a much better method of depositing refractory metal silicide films.
A particularly excellent candidate metal silicide material is TiSi.sub.2 because of its lower resistivity compared to other refractory metal silicides.
To our knowledge, attempts by others to devise a satisfactory CVD process for depositing polycrystalline films of TiSi.sub.2 have been unsuccessful.